Kennewick man charged with murder in fatal stabbing

A Kennewick man has been charged with second-degree murder for allegedly stabbing the boyfriend of his estranged wife in front of dozens of people at a local plasma donation center.

Prosecutors announced the murder charge against Matthew H. de Vore, 40, at a news conference Wednesday at the Benton County Justice Center.

The charge carries an aggravating circumstance that alleges the death of Thomas R. Christian Sr., 45, had a destructive and foreseeable impact on others. The aggravating circumstance would allow prosecutors to ask for a sentence above the standard range.

Prosecutors are working with Kennewick police to determine if the stabbing was premeditated, which could lead to an increased charge of first-degree murder, said Benton County Prosecutor Andy Miller.

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Christian was killed with a kitchen knife Monday as he sat in the waiting room of Biomat USA, a blood donation center, on North Union Street with his girlfriend Brenda de Vore.

She and Matthew de Vore are divorcing after an 18-year marriage.

Court records show Matthew de Vore has a history of domestic violence with his wife and family dating back to 1999. He was recently sentenced to 10 days in jail for assaulting his teenage son in a store parking lot.

Christian’s mother, Virginia, told the Herald she believes the murder was premeditated and Matthew de Vore should be charged with first-degree murder. She said he had previously threatened her son.

“I don’t like the (second-degree murder charge) because I told the detective yesterday that from what I understand he was threatened,” Virginia Christian said from her Marysville home. “How in the heck did (Matthew de Vore) know he was going to that blood blank? He had to follow them there. Why would he be there with an 8-inch kitchen knife?”

Investigators are checking into some information about how de Vore knew the couple would be at the plasma center, Miller said. But that information was not released Wednesday because the investigation is ongoing. Prosecutors and police declined to discuss other details about the case.

“Part of the problem is if potential witnesses read about what other witnesses say in the media, that can influence their memory or what they tell investigators,” Miller said. “We want to keep this investigation as clean as possible.”

An autopsy performed by a forensic pathologist Tuesday showed Christian was stabbed one time through the chest with an 8-inch kitchen knife. He died at the scene.

Christian had recently moved to the Tri-Cities to reconnect with Brenda de Vore, whom he dated in high school, family members said. He had six biological children, multiple grandchildren and was a father figure to others.

Christian grew up in Stanwood, owned a taxi company in Idaho Falls for years and had plans to move with Brenda de Vore to Tennessee, family members said. He owns property in Tennessee had dreams of one day living there with his family.

Christian’s daughter, Miranda, spoke about her father during the news conference. She said her large family is struggling to make sense of Matthew de Vore’s actions.

“I want him to look at me,” she said. “I want him to look into all my brothers’ and sisters’ eyes and realize he took him away from us.”

De Vore was arrested at a grocery store near the blood center. Witnesses chased after him and eventually surrounded him until police arrived. Some even reportedly threatened him with large rocks.

Kennewick Police Chief Ken Hohenberg said authorities plan to honor citizens who helped the day of the stabbing.

Virginia Christian told the Herald it brings her some peace knowing strangers went out of their way to help her son and apprehend de Vore.

“I am very, very proud of those people who chased him down and kept him there until the police came,” she said. “There’s not too many people who want to be involved in something like that.”